If you're sold on the 5X and having a phone that has a shoehorned fractal antenna supporting too many LTE frequencies with mediocre reception into one device so you can activate it on any of the big four carriers, then that's what you're going to have to buy. Maybe consider used/refurbished instead if the (quite unreasonable) price is putting you off.
This said, if you're seriously only wanting to do this so you can bail out for the GSM MVNO pastures (excuse Google Fi's schitzophrenic T-Mobile/VoLTE service) after trying and potentially failing with the cut-rate Sprint carriers, why do you need Verizon activation support? Pick up a used Nexus 5 instead for a whole lot less.
I really don't have much more to add to this other than words of caution. You apparently already killed one smartphone's SIM slot. Consider how frequently you plan on jockeying SIM cards in the future and the fact that damaging pins on a friction based, side load nano SIM slot on a $400 phone would yield similar results to your current situation. Unfortunately, SIM slots just aren't designed to handle heavy card swapping. As such, factor handset costs along with service cost and carrier quality, and try to just stick with one carrier that will serve you well long term. Odds are, spending a bit more month to month with one provider and not potentially swapping out multiple SIM cards on a regular basis to reduce wear and tear on one of the most expensive mechanical failure points might cost far less money than possibly jockeying between the cheapest deals and having an expensive phone fail prematurely.
I don't know what your past and current setup and usage history looks like, and I don't know what you have planned moving forward... but is is something to consider if it's on your mind. Just like with contract handsets, you should consider the sunk cost of that handset in your monthly service costs across its service life as well if you're going to engage in behaviors that will yield in premature/unnecessary hardware failure.
Saving even ten bucks a month is pretty worthless if it leaves you buying new $400 phones every two years instead of four.
