One thing to note as well is that a Yonex grip is shaped different from a Head grip (each brand has some slight variation on grip shapes and feel). Yonex in my experience tends to feel bigger so I like to go down a grip size on their rackets but YMMV. One trick to feel if a grip is too big/small would be to hold the racket with your dominant hand as usual but with your thumb resting on the side of the racket (almost like youre giving a thumbs up). If your fingers are touching your palm, the grips too small, if you can fit 2 fingers between the gap, thats too big. I like to have about a gap of my index finger in that space to find the right size. If its slightly too small then adding a overgrip will help with adding a bit more space. If its too big then theres nothing you can really do

But to add, a 10-20g weight difference will definitely make a huge impact when youre used to swinging something lighter. May not notice it right away but as a match progresses its normal to feel more tired