how often is ucas extra worth it?

hi, im doing an access to he course in computing atm. i wanted to do maths but there werent any souly maths courses in my area so i thought computing wld be he next best thing. When it came to actually applying for unis i realised that pretty much no unis accepted my course for first year maths so i just ended up applying for compsci courses but i think i wld rather to have to do a foundation year in maths.

How likely is it to be accepted on a maths foundation year with ucas extra? should i just wait until clearing?

You say you "ended up applying for compsci courses". Do you have any offers? Are you saying that if one of those offers turned into a confirmed place on results day (because you met the grade requirements), that you'd decline it in order to pursue a Maths with Foundation Year degree via Clearing? If so, then why not decline the offers now and apply for Mathd with a Foundation Year via UCAS Extra? What's the down-side? You don't want to study Computer Science anyway.
Have you checked the entry requirements for Maths with a Foundation Year courses which are available via UCAS Extra? Would they accept your Access to HE course?

yea theres quite a few courses available that'd accept my course+grades i just dont know how risky it is ig? like is there a high likelihood ill just end up with no options for uni bcs then its just not worth the risk

If there are "quite a few courses available that'd accept my course+grades" then the risk is low. But I agree there is risk, especially as you don't actually know (presumably) what grades you're going to achieve in your Access course.
It all boils down to your appetite for risk vs. your desire to switch from Computer Science to Maths with a Foundation Year. As that's something only you can determine.

most of the courses need 80 ucas tariff or less, ive already gotten enough distincions to guarentee that ill get at least 93, so is it fairly low risk?

Agreed.