@lifeenjoyer69 Hello and welcome. Quick run through of the channels
Edge- Dragons live here only for the very experianced devs
Devel- Where the latest updates get tried out and tested You can expect the odd issue on this channel. Updated daily.
RC-The last testing branch before a stable release Updated now when there are real changes that need testing.
Stable- Good solid everyday usage channel. This will be updated on a cycle of on average 12 weeks. (There is a new update OTA-23 on Tuesday 28th June).
This system is followerd throught the year so in effect they are on a continues roll out. So you will get updates on a regular basis. So if you want small daily changes try devel it is 80-90% without issue but can go down hard.
One of the great strengths of Ubuntu Touch (the OS) is the UBports Community behind it yes a few dev do get paid but the vast majority of the work is carried out by volunteers and enthusiasts. It is a very supportive, helpful community and welcoming community whatever you plan on doing or how you use your UT device. That is point it is your phone do with and use as you want.
Please have a look round and read through the Forum there is plenty of info and help here. The pixel 3a is a great device (I got one a few weeks ago) so the xl should be the same. Give it a go all the help and advice you need is here.