Second opinion on a 27 year old’s tax situation please 🙏🏼

Hello,

I’m a 27 year old, living in Zone 5 in London.

I’ll summarise the situation below: - I’ve started a new job, my annual pay is £62,000. - My new employer matches up to 3% (awful I know, but I’m going to contribute 3% to get the match). - I have a Plan 2 student loan. - I have a Postgraduate loan. - I have 2 existing pensions totalling around £20k. - I invest £910 per month into S&P500 on Vanguard. - I have some other ad-hoc investments on Trading 212. - I already have a car, laptop etc so I feel like salary sacrifice isn’t an option (however I will be sacrificing for health benefits/life assurance etc).

What exactly should I do to get my taxes in order and pay less to the tax man for the highest possible returns? I hear higher pension contributions decrease tax liability, but I feel as though whatever money is leftover after my monthly pay is better invested into the markets based off return alone?

TLDR: I’m just trying to figure out if I should pay more into my pension; or invest my money into ETFs and see which is more likely to make more money in the long run.

Thank you so much, please ask if you need any more information!

PS: I had no idea this community existed but I’m so grateful for Reddit and wonderful people like yourselves who are willing to offer a second opinion!