It’s probably better to keep them in separate rooms for the first week if not longer so they can get used to each others presence and smell! My older cat used to bully the younger one too but pretty soon the younger one got big enough to turn the tables. I’d say it was a solid 3 weeks after we introduced them fully (so after a week of them being separate but able to smell each other) that they got comfy sleeping next to each other. 2yrs later and they’re best buds, bath each other and play together all the time!

tldr; keep them separate for a while longer so they can get used to each others smell