brent Installing tons of applications don't impact the performances as long as they are not running... It just consume more disk space. The problem with AUR is that you can find anything there: good stuffs but also unmaintained things, badly packaged applications, packages abandoned by their maintainer or not updated at the same rhythm as the core stack resulting in breakages, it already happened that some package contained malwares or crypto miners, it's not always clear for the end user if the package is built from source or if it's a binary that is packaged, experimental/unstable things are also available there, some package are illegal, etc. So it might be handy but it might be awful as well. People who use AUR should check the packages.
Regarding the number of services, well having useless services running isn't a good thing, but just focusing on the number of enabled units is just stupid !
A very obvious example of less doesn't mean better : stop the networkmanager service and you won't have network/internet connectivity anymore !
Also some units are targets : their are used for grouping units, sockets are just listening on IP/ports but aren't daemons as such and timers are the equivalent of cron/scheduled tasks -> if you schedule a task to run every 30 days, it will use resources only when it's running not all the time and it could be for very useful things like performing logs cleaning, trimming a SSD drive, backups, etc...
So yeah Ubuntu enable lot of things, it's a choice they make to have a maximum amount of things working out of the box and thus offering a great user experience. This of course bloat the system and distos like Solus don't want that and try to offer a good user experience without enabling tons of stuffs "in case somebody would need it".
-> My criticism is that 90 vs 24 is an indicator but it's completely meaningless since absolutely no analysis of what is loaded and why.
