Dear Maintainer,
Sharing a session so the problem will be easy to know -

$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
The following packages have been kept back:
  fonts-liberation fonts-liberation2 libgeos-c1v5
The following packages will be upgraded:
  curl libc-l10n libcjson1 libcurl3-gnutls libcurl3-nss libcurl4
libcurl4-openssl-dev libpcre2-16-0 libpcre2-32-0 libpcre2-8-0
libpcre2-dev
  libpcre2-posix3 libplexus-compiler-java libpython3.10
libpython3.10-dev libpython3.10-minimal libpython3.10-stdlib
libwine-development
  libxnvctrl0 libyajl2 openjdk-17-dbg openjdk-17-demo openjdk-17-doc
openjdk-17-jdk openjdk-17-jdk-headless openjdk-17-jre
  openjdk-17-jre-headless python3-nbformat python3-tifffile
python3-zeroconf python3.10 python3.10-dev python3.10-minimal
33 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.
Need to get 483 MB/497 MB of archives.

$ sudo debdelta-upgrade
Delta is not yet ready in the server:
fonts-liberation_1%3a1.07.4-11_1%3a2.1.5-3_all.debdelta
Delta was not created since new package is too small:
fonts-liberation2_2.1.5-1_1%3a2.1.5-3_all.debdelta
Delta is too big: libgeos-c1v5_3.11.1-1_3.12.0-1_amd64.debdelta
Delta is too big:
libplexus-compiler-java_2.12.1-1_2.12.1-2_all.debdelta
Created,    time  0.60sec, speed 89kB/sec,
libpcre2-posix3_10.42-2_amd64.deb
Delta is not yet ready in the server:
libwine-development_8.1~repack-1_8.3~repack-1_amd64.debdelta
Created,    time  0.31sec, speed 42kB/sec,
libxnvctrl0_525.85.05-3_amd64.deb
Created,    time  0.27sec, speed 82kB/sec, libyajl2_2.1.0-5_amd64.deb
Delta is too big: openjdk-17-dbg_17.0.8~6-3_17.0.8~6-5_amd64.debdelta
Downloaded, time  0.25sec, speed 6527B/sec,
openjdk-17-jre_17.0.8~6-3_17.0.8~6-5_amd64.debdelta
Created,    time  0.76sec, speed 230kB/sec,
python3-tifffile_20230710-1_all.deb
Downloaded, time  0.26sec, speed 18kB/sec,
libcjson1_1.7.15-1_1.7.16-1_amd64.debdelta
Downloaded, time  0.27sec, speed 19kB/sec,
python3-nbformat_5.5.0-1_5.9.1-1_all.debdelta
Created,    time  0.40sec, speed 175kB/sec,
python3-zeroconf_0.71.0-1_all.deb
Downloaded, time  0.34sec, speed 51kB/sec,
openjdk-17-demo_17.0.8~6-3_17.0.8~6-5_amd64.debdelta
Created,    time  0.49sec, speed 366kB/sec,
openjdk-17-jre_17.0.8%7e6-5_amd64.deb
Created,    time  0.16sec, speed 136kB/sec,
libcjson1_1.7.16-1_amd64.deb
Downloaded, time  0.39sec, speed 63kB/sec,
libpcre2-32-0_10.42-1_10.42-2_amd64.debdelta
Downloaded, time  0.40sec, speed 75kB/sec,
libpcre2-8-0_10.42-1_10.42-2_amd64.debdelta
Created,    time  0.47sec, speed 94kB/sec,
python3-nbformat_5.9.1-1_all.deb
Downloaded, time  0.37sec, speed 83kB/sec,
libpcre2-16-0_10.42-1_10.42-2_amd64.debdelta
Downloaded, time  0.57sec, speed 148kB/sec,
libpcre2-dev_10.42-1_10.42-2_amd64.debdelta
Downloaded, time  0.98sec, speed 672kB/sec,
openjdk-17-jdk_17.0.8~6-3_17.0.8~6-5_amd64.debdelta
Downloaded, time  0.54sec, speed 1761kB/sec,
openjdk-17-doc_17.0.8~6-3_17.0.8~6-5_all.debdelta
Created,    time  2.49sec, speed 1614kB/sec,
openjdk-17-demo_17.0.8%7e6-5_amd64.deb
Created,    time  0.45sec, speed 501kB/sec,
libpcre2-32-0_10.42-2_amd64.deb
Downloaded, time  0.53sec, speed 3273kB/sec,
openjdk-17-jre-headless_17.0.8~6-3_17.0.8~6-5_amd64.debdelta
Created,    time  0.28sec, speed 915kB/sec,
libpcre2-8-0_10.42-2_amd64.deb
Created,    time  0.29sec, speed 836kB/sec,
libpcre2-16-0_10.42-2_amd64.deb
Created,    time  1.40sec, speed 525kB/sec,
libpcre2-dev_10.42-2_amd64.deb
Downloaded, time  2.42sec, speed 6316kB/sec,
openjdk-17-jdk-headless_17.0.8~6-3_17.0.8~6-5_amd64.debdelta
Downloaded, time  0.38sec, speed 253kB/sec,
libplexus-compiler-java_2.12.1-2_all.deb
Downloaded, time  0.02sec, speed 3923kB/sec,
libgeos-c1v5_3.12.0-1_amd64.deb
Downloaded, time  0.02sec, speed 249kB/sec,
fonts-liberation2_2.1.5-3_all.deb
Downloaded, time  0.15sec, speed  9MB/sec,
fonts-liberation_2.1.5-3_all.deb
Created,    time  3.52sec, speed 1195kB/sec,
openjdk-17-jdk_17.0.8%7e6-5_amd64.deb
Created,    time 65.79sec, speed 191kB/sec,
openjdk-17-doc_17.0.8%7e6-5_all.deb
Created,    time 40.12sec, speed 1065kB/sec,
openjdk-17-jre-headless_17.0.8%7e6-5_amd64.deb
Created,    time 19.77sec, speed 3522kB/sec,
openjdk-17-jdk-headless_17.0.8%7e6-5_amd64.deb
Delta-upgrade statistics:
 total resulting debs, size 133MB time 147sec virtual speed 930kB/sec

$ sudo aptitude installibcjson1 libpcre2-16-0 libpcre2-32-0
libpcre2-8-0 libpcre2-dev libpcre2-posix3 libplexus-compiler-java
libwine-development libxnvctrl0 libyajl2 openjdk-17-dbg
openjdk-17-demo openjdk-17-doc openjdk-17-jdk openjdk-17-jdk-headless
openjdk-17-jre openjdk-17-jre-headless python3-nbformat
python3-tifffile python3-zeroconf fonts-liberation fonts-liberation2
libgeos-c1v5 5
The following NEW packages will be installed:
  fonts-liberation-sans-narrow{a} libgeos3.12.0{a}
The following packages will be REMOVED:
  libgeos3.11.1{u}
The following packages will be upgraded:
  fonts-liberation fonts-liberation2 libcjson1 libgeos-c1v5
libpcre2-16-0 libpcre2-32-0 libpcre2-8-0 libpcre2-dev libpcre2-posix3
libplexus-compiler-java libwine-development libxnvctrl0 libyajl2
openjdk-17-dbg openjdk-17-demo openjdk-17-doc openjdk-17-jdk
  openjdk-17-jdk-headless openjdk-17-jre openjdk-17-jre-headless
python3-nbformat python3-tifffile python3-zeroconf
23 packages upgraded, 2 newly installed, 1 to remove and 13 not upgraded.
Need to get 482 MB/485 MB of archives. After unpacking 1,871 kB will be used.
Do you want to continue? [Y/n/?] n
Abort.

Just to make sure that this is not a false bug. I used aptitude to
show me the package size of fonts-liberation-sans-narrow as well as
libgeos3.12. Both are less than 1 MB. I even tried fonts-liberation
package and that too is only 5 MB. So seems debdelta-upgrade doesn't
function, dunno why :(