Well, for me, pre hrt. i was very strong, could pick up very heavy things, and could do heavy physical work. Never had huge muscles though, but i did have the strength!
Now, wanting to lose most of my muscles due to being rather large framed, i tried to avoid as much physical activity as possible after starting hrt. Now, 10 months later, I am VERY much weaker, and if I do try exerting myself by picking up something a bit heavy, or picking something up incorrectly, i suffer for a day or two afterwards.
So, for me, YES, i have gotten substantially weaker...
Others have said, continue working out after starting hrt to keep some of your strength.
I did not, and this is where i am now, but i am not complaining at all.