As somebody who always maxes out RAM I have to second that.
If you have a HDD, the most massive improvement will arise form just swapping in an SSD. I remember doing that several years ago with my 2010 15" MBP and the SSD made it feel like a brand new Mac. It was tremendous. The HDD->SSD improvement cannot be overstated.
65GB is next to nothing in Photos, but get away from iPhoto as soon as possible, if it was not a spelling error. It really feels old in many bad ways too. But regarding size of Photos Library, I have 985 GB in iCloud Photos in one big bunch. (about 72.000) and have no problems on any of my devices. Great to have photos stored a secure place and access to all from all my devices.
On the other hand, shooting Canon .cr2-raw files in portrait turns them into landscape when importing into Photos on Catalina, so I do all imports to Photos on my Mac running Mojave still - and do not count on upgrading soon.
For metadata, I use HoudaGEO, that will not just add location, but also all the metadata I used to add in Aperture, and frequently use a different app like ON1 to sort and filter the photos before importing to Photos, as I shoot using bracketing and hence get far more photos than I want to keep - and spend time uploading, not the least.
One thing, btw.: Be sure to let Photos (or iPhoto for that matter) do its housekeeping, i.e. do not quit the application immediately, but let it run for some days to let it index everything it needs to, as this may take some ressources if it has never finished the first run of this.