Memory consumption is too high and never stops

I love elementary OS, but it still needs a lot of optimization.

I restarted my laptop at 12:30. I haven't clicked anything for 10 minutes. Then I ran the Optimizer app to check memory usage and LibreOffice Writer to write down observations.

There are some AppCenter processes that run in the background all the time and consume far too much memory. Time passes, but memory consumption does not decrease, just stands still or increases. I haven't started the AppCenter since rebooting. There are no pending updates.

12:41
213 MiB – io.elementary.appcenter -s
90 MiB – pantheon-mail --hiden
85 MiB – LibreOffice Writer opened with short text document (flatpak)

12:43
213 MiB – io.elementary.appcenter -s
130 MiB – pantheon-mail --hiden
85 MiB – LibreOffice Writer opened with short text document (flatpak)

12:44
91213 MiB – io.elementary.appcenter -s
155 MiB – pantheon-mail --hiden
85 MiB – LibreOffice Writer opened with short text document (flatpak)

12:48
216 MiB – io.elementary.appcenter -s
191 MiB – pantheon-mail –hiden
86 MiB – LibreOffice Writer opened with short text document (flatpak)

13:26
217 MiB – io.elementary.appcenter -s
203 MiB – pantheon-mail –hiden
90 MiB – LibreOffice Writer opened with short text document (flatpak)

13:41
217 MiB – io.elementary.appcenter -s
203 MiB – pantheon-mail –hiden
92 MiB – LibreOffice Writer opened with short text document (flatpak)

Another thing is the memory consumption by the mail client. I have enabled checking for new emails even with the app closed, so I understand why this process is there, but I think we'll all agree that 100-200 MiB is very high consumption for such a process. The LibreOffice where I write these conclusions consumes at the moment about 92 MiB.