your questions have probably been answered already but I will offer my 2 cents.
if you don't want to take a gap year then I suggest you don't. taking a gap year just to study for the UCAT is not worth the time off because 1. there's still a chance you won't make it to med, and 2. it'll be a complete bludge year of zero productivity if all you're doing is studying for UCAT. if you're also working, volunteering, picking up new skills, travelling etc. then a gap year imo would be worth taking to then pursue med, it needs to be a planned productive experience not a time to laze around and not gain much from. personally a gap year to try again for med would not have been good for me, because I'm lazy asf and if there's no pressure in my life I'll spiral into bad habits and lose the momentum I graduated high school with
I think you should study law (or anything else) for first year and sit the UCAT as well, if you get into med then you can transfer to med, if you don't get into med, you can continue with your law degree. my friend is doing engineering this year (first year) and she (re)sat the UCAT as well, idk if she heard back from any uni's regarding med but if it doesn't work out for her, then she'll continue with engineering which is obviously employable and not a risky one like medical science
for those saying prestige, pay and academic success (which is not flexing btw) should not be the main contributing factors in which degree you pick, I very much agree. but I don't think anyone should be shamed for picking a degree based on these factors.
I've gotten shamed for pursuing dentistry because it's the "next best thing to med" and not because I wanted to, and it's so ridiculous lol. like stfu and mind ur own business not everyone has a dominating passion as they leave high school, and sometimes thinking of prestige and what path matches one's academic levels can help give a sense of direction when you're lost or unsure. btw now I love what I'm studying, it's just that one year ago during HSC, I had no idea what I was interested in so I just picked degrees based on prestige and academics and minor interest, nothing wrong with this at all. I still managed to prove to interviewers that I wanted to do dentistry despite picking it for largely other reasons, but now I genuinely want it it just took some time after school to realise