With a hyperthetical USD 50,000 would you invest in bitcoin or use the money to fund a margin trading account
Just invest it and hold.
You could take $5k and make a decent amount on margin while keeping the $45k on the exchange - I wouldn't go higher than $5k though.
(the trades will all be made by trading bot handled by signals group with 100% return)
How sure are you that this will work and return a profit? A lot of signals groups (especially if they lose leverage) don't turn a profit - some do but the majority probably don't and most pass the trades they have higher certainty on to the free channels in advance or lie about their potential profits (as in saying how much they'd make if they went in at the buy price and sold at the last take profit - which wouldn't be done in anyone's strategy as the win rate would be ridiculous)