I’ll address this on a broader scale for all readers.
The procedure is called orchiectomy, orchi for short. As well as the physical change It does mean the end of production of the vast majority of testosterone. The body still can produce some in the adrenal glands, but more on the level of what GG’s produce, This is actually more healthy than zero T, not to mention providing for labido.
Some people opt to do orchi surgery prior to GCS, SRS or whatever name you want for bottom surgery. One caution is that in bottom surgery the sack skin is typically used to form some of the features of the constructed female anatomy. The absence of testicles can lead to atrophy of this skin and make it harder to get the desired look without grafting.
You really should talk to your physician and surgeon about this. Do your homework and good luck, we’re all here for you.