What do you recommend for this MTB'er with an odd schedule!?


I am a new Zwifter with an odd schedule. I split time (starting this June) between Bend OR, and Phoenix AZ. I am essentially back and forth every other week. In Bend I ride mostly mountain bike but occasional gravel and road. Most rides are 1.5-3hrs.(1000-3000ft of climbing) I set up zwift (wahoo kicker and climb)in my Phoenix house because I work 12 hour shifts when I’m in town and loath riding in the Phoenix summer heat. My thought is an hour or so after work on zwift and similar on days off in Phoenix (5-6 days a week). I’ve mostly used zwift riding solo but also did a group ride last night which was super fun. I also did an FTP test…meh results 227W with 2.5W/KG

My question is how can I use zwift to 1)become stronger on the mtb 2)not go crazy staring at a screen 3)should I consider a training program even thought i’m only around every other week or so? 4)Any other hints or tricks to get the most out of zwift? 5)should I be training specifically to increase my FTP? 6)Can I increase endurance only riding an hour or so (much longer and I get board on the trainer)

Thanks in advance for an help/suggestions

Doc Jay