The next meetup will be in around 3 or more month.
We just come together 3-4 times a year.
Right now you have the following options for the FP5:
DivestOS is not (yet) support for the FP5 but - I like his comparisons:
Patch History - DivestOS Mobile (so /e/OS and iodéOS seem to be a bit slow with patching from time to time)
Also nice and very detailed:
I use iodéOS right now (was one of the first available ROMs and I was able to remove everything which I don’t need more or less easily) and I plan to move to CalyxOS one day (still in Beta right now).
If you wanna stay LineageOS based, you only have the choice between iodéOS and /e/OS right now.
Regarding "Banking apps (they differ in detail) - I don’t do banking on my phone, but if, I would not try to fight against their mechanisms to detect root, no-gapps or an unlocked device. So I would probably install microg, do not root and relock the bootloader.
Ah and a comment about bricking or the risk of it:
The dangerous part is the relocking of the bootloader (the “functionality” is called “anti-rollback feature”). I recommend to read (expand the details) the red boxes in /e/OS install guide Install /e/OS on a Fairphone FP5 - “FP5” . Imho it is clearly described that the OS, you wanna switch to, should have the same or a newer “Android security update” (that it the name in the settings - at least here - they call it "“Android Security Patch Level” ) then the current installed one. So when you get back your phone (I agree, it will most probably have FairphoneOS installed then), you should check that and wait until your preferred ROM gets updated to the same or a newer level/date. So self-explanatory it is also recommended to not update the currently installed ROM. 