FTP not improving

I’ve been cycling and doing triathlons for a few years now. My current cycling training looks like:

4 rides /week (6-8 hours)

• 1 zone 2 ride
• 1 interval ride
• 1 recovery spin
• 1 long ride

Current FTP is 198 (3.05 w/kg). I’ve never been able to get my FTP higher than like 205. I would say I’m currently at my peak bike fitness. Rode a century this weekend in 5 hours.

Is my training just not targeted at increasing FTP? Should I add another interval ride? Or am I genetically limited?