I've kept my gym routine up throughout the journey so far. And that has been fun on a social and body image factor.
I have lost considerable upper body muscular strength. Yet I do the same exercises. I have gained some 'bum' weight, pure fat I think, it wobbles and I quite like that

I also have some wobbling in the boob region, and I really like that

Leg strength hasn't changed much at all. I haven't increased my leg weights, and I was doing so before HRT, but I have not decreased them. Upper body weights: and I have never been a builder of my upper body muscle ever, but my weight tolerance for squats, etc is markedly reduced. I'm squatting 50-75k and sweating. I was doing 150k pre HRT. I ask guys to bring weights to the machines for me. It is an old gym so some machines we have to load with free weights

. There has been no issues about this, the guys have been great, they do so for all the female members who ask them. They are gym rules BTW that people help each other with moving weights.
I eat a high protein diet of lean meat. Few carbs, a lot of fruit, an egg for breakfast no butter or marge on my toast. lunch is a sandwich with lettuce tomato and either low fat cheese or low fat meat. I also have another fruit and drink water. I drink tea with no sugar or milk.
I weigh 65 kilos. I have essentially kept that weight from when I was 18.