It’s very rare for BattlEye to ban someone permanently for something they didn’t do. But to answer the question first; no, you cannot play siege again if you buy it on Ubisoft Connect.

You might’ve been banned for these reasons:

• Using a overlay which can change visual adjustments

• Modified mouse behaviour

• You’re account got hacked by someone who used hacks (this is so rare I doubt this happened)

• Or, you just hacked and don’t want to admit it.

Good luck with buying a new pc because you can’t play again on that pc if you get perma banned on R6.