Thinking about getting an implant?

Hello everyone. Im thinking about getting an implant. Just to be clear i can have an erection…my problem is the duration. I ve been trying various spray for dealy ( so far not working too well, sometimes too much other times not enough). So this lead to many insecurities and so on and on. Now i have many questions and even more fear ( just by writing about a possible operation im covered in sweat). First: do the penis stays erect as much as i want? I dont care about my orgasm but i want to know how long can stay erect ( does it stays erect after i c…m?). Also what abou the lenght? Mine its not that great but i heard that (somehow) you can lose a bit after the operation? Could be possible to do both this operation and then something to increase the lenght in case of losing some ? ( also do you lose on full erect or on normal). And how it exactly it works for “activating” and “deactivating” ( spell it out like you are talking to a baby). Which type of doctor should i consult first? How long i must wait before using the implant after the operation? Musr i change the implant every tot years?

Im gonna apologize if this all seems a noncoherent rambling but i swear i get nervous even writing about this.

Also sorry for my english , its not my first language im not from the US.