Chemistry BSc+MSc at a more internationally reputable university, or MChem

Currently an MChem student at the University of York.
I have a dilemma: should I drop to a BSc at York, then look for an MSc program at a more internationally reputable university, or should I continue on the MChem at york.
The main considerations are :
1) the undergraduate loan for the MChem is nicer than the undergraduate loan + the MSc loan
2) employability with the MSc from a top uni.
Thoughts on the best move?

Depends on what you consider "more internationally reputable"

What's your goal after the degree?
How will you be funding the standalone masters for that option (note you have much more limited funding if being funded by SFE for this route)?

I have money saved up from being very frugal during my time at York. I'd still need to take out a postgraduate loan, though.

My goal after university? I'm really not sure... I just want to have the most options and be the most desirable to employers as I can possibly be. I've been looking into patent law, but that's still a very nascent plan.

Realistically outside of investment banking or management consulting which uni you went to isn't going to be a big factor (if at all). For those areas I think it might be more realistically expected a masters at a target uni be done in a relevant area, as while they accept any undergrad degree I am not so certain "non-target unrelated undergrad to target unrelated postgrad" is going to be as acceptable as "target unrelated undergrad" or "non-target unrelated undergrad target related postgrad".
I think you're overestimating the importance of that element. Most employers don't care where (or what) you studied and some actually recruit "blind" where they don't reveal your uni to the people deciding on whether to offer you a role or not to avoid bias. Note much more important than what uni you go to is what relevant work experience and internships you've gotten, how prepared you are for assessment centre days and psychometric tests etc. Doing the MChem gives you an "extra" summer for internships specifically targeted at undergrad students (some of which may not be available you when going from graduating with the BSc to a postgrad course elsewhere).
Honestly I don't see any compelling reason for you to change university (by graduating with the BSc and then doing a masters elsewhere) so far, unless you have experienced some kind of specific trauma at your current uni and can't bear to stay in the area or have some caring commitments or medical requirements to be in a different area?

So why do people care so much about getting into a top institution if it's ultimately unimportant? I find that hard to believe

Uni of York is one of the best unis for chemistry in the UK though? It's consistently top ~7. Why wouldn't you complete your mchem there ???

So why do people care so much about getting into a top institution if it's ultimately unimportant? I find that hard to believe

Job market is buggered at the moment- I know MEng Cambridge students who can't get a 25k engineering job.
What uni, and what you study unless it's medicine and you're going into medicine does not matter. It's difficult for everyone. What's particularly important now is getting as much work experience as possible while at University to make you stand out as 50% of the population have gone to university and just going to a red brick does nothing for you anymore