Unless you are getting some kind of financial incentive for the first firm or there is something in either the contract/offer letter in either the TC or SVS offer that says you can have other employment, you could just hold on to your current offer and then renege if you got your first choice
That’s my issue. I already study for the GDL, part-time, so won’t finish until summer 2021. They would take over the payment, so I’m not sure what the right thing is in the situation.