I feel your pain ,I have the same rims and had the same issues it was almost always the valve , I have muc off valves and was using the wrong rubber adapter as they come with a few different shapes to fit different rims , and I either had the valve too tight or too loose.
Also I use t rex gaffer...
I have size 12 feet using 5.10 freeriders and DMR V12,s have been a good combination for me won't break the bank at about £40 and I've not had any issues .
First bike was a hard tail then moved onto a full sus and couldn't believe the difference suddenly stair sets were a breeze boulder fields no problem and jumps are easier too since you can compress the bike to "pop" of the lip.
Maintenance on a full sus is minimal maybe just a shock service...
Hi folks finally got my new ebike after only a 6 month wait ? (cube stereo hybrid 120) and can finally post as a newbie emtb rider ,and have to say the switch from analogue to e bike is ridiculous I can't take the silly grin off my face ?.
Ian.