If I redeem my three-month game pass card, will that cancel my year subscription to Xbox...

When renewing an Xbox Game Pass Ultimate subscription it converts the three months xbox live to 1 month xbox live. You can wait untill the subscription has fully ended to redeem three months of xbox live. I recommend buying many months or a year of xbox
live then buying one month of game pass ultimate it will change the whole subscription to xbox game pass ultimate. This can only go up to 36 months

If it's regular Game Pass it won't have any effect on your Gold.

If it's Game Pass Ultimate, it will upgrade your remaining Gold subscription to Ultimate. So if you still have 12 months left on your Gold and you add the 3 month code, you'll have 15 months of Ultimate.

Currently I have Game Pass Ultimate subscription with recurring billing off and don't want this subscription service once it expires 10/22/22, so do I just activate my prepaid xbox live gold subscription card on 10/23/22, or do I actually have to cancel game pass ultimate subscription for my account on 10/23/22 manually before redeeming and activating my xbox live gold prepaid 12 month card on 10/23/22?

Also, if you select turn off recurring billing on your account for your current game pass ultimate subscription, does that automatically cancel your prepaid game pass ultimate subscription on its expiration date? or is it requirement that you still manually cancel Game Pass Ultimate on or after its prepaid expiration date if you wish to switch back to xbox live gold using a prepaid subscription card?

Currently I have Game Pass Ultimate subscription with recurring billing off and don't want this subscription service once it expires 10/22/22, so do I just activate my prepaid xbox live gold subscription card on 10/23/22, or do I actually have to cancel game pass ultimate subscription for my account on 10/23/22 manually before redeeming and activating my xbox live gold prepaid 12 month card on 10/23/22?

Also, if you select turn off recurring billing on your account for your current game pass ultimate subscription, does that automatically cancel your prepaid game pass ultimate subscription on its expiration date? or is it requirement that you still manually cancel Game Pass Ultimate on or after its prepaid expiration date if you wish to switch back to xbox live gold using a prepaid subscription card?

If, at a later date, I want to consider switching back to game pass ultimate service again after already activating up to 36 months of prepaid xbox live gold subscription cards, then the option to convert these 36 months of xbox live gold to game pass ultimate at a 1:1 monthly ratio conversion for a 2nd time all over again is still offered to me correct? the only difference this time around would be that I would have to pay $14.99 or whatever the current monthly game pass ultimate price rate is for one month to convert all prepaid live gold months at 1:1 ratio? since I can't qualify for the $1 per month ultimate promo price deal since I already used that 3 years prior?

Yes, you need to give credit card details so that if you decide to carry on the subscription, it will work, and then it goes on to automatic billing. This means that you have to give your credit card details to redeem the Xbox Game Pass. After doing that, you will be able to go into "My subscriptions" in settings and cancel the Game Pass for when it next renews.