Congratulations on your progress. I'm in more or less exactly the same spot as you, having dropped a similar amount of weight in a similar span of time. No significant loss of strength for me, which I'm thrilled about. If you just started lifting in January I'm probably carrying more LBM than you though.
I've had success with simplicity, and I'm expecting that this will continue for a while longer. I eat meat and vegetables. Then I have some more vegetables. Eggs, nuts and protein powder are also on my menu. I limit carbs, except for my workout drink. I lift with heart. I still cheat on the weekends and progress continues.
Are you sure you've picked all of the "low hanging fruit", so to speak? No pints of Ben and Jerry's once a week? No sneaking in a sixer of IPA here and there? Are you certain that your macros are what you're actually eating, or is that just what you THINK you are eating?
I don't know much about intermittent fasting, but I do know quite a bit about being a 275+ pound dude. I believe you should still be able to make good progress by adjusting your intake down just a little bit and continuing doing what you are doing. No need for fancy methods or radical changes to an approach that you've been having success with..
My last adjustment like that was simply cutting out whole milk. Just like that, back on the progress train.
What does your lifting look like?