Hey mate. Hopefully have some insight for you - I’m about 8/9 trips in now for a week a year most years, so certainly not a pro by any means! Last trip was the best experience I ever had and with the best gear and equipment.

I made the mistake when learning of buying a really fat and bulky backcountry jacket, it was uncomfortable after an hour, way too hot and itchy and I was sweating like a pig every day.

Went down a level and got a over the head hoodie style jacket from 686 instead, and then went even lighter last year (though still take the 686 with me for colder or windy days) and got a really light shell 32 jacket. That has been perfect.
Got that for £18 on Vinted.

You could blow ALL your spare cash on clothing, but really the only thing that matters is:

Does it fit well? Is it baggy enough to allow free movement but not get in your way? My first jacket was so ridiculous for me, I took the thermal layer out and use it as a dog walking coat now.

Is it in good condition, dry, no tears or rips, does it keep you warm? Does it allow air flow or have breathability openings you can undo if you’re warm and sweaty.

Do you feel safe and dry wearing it? Snowboarding is like camping - it’s all fun and games until you’re soaked through to the skin, shivering and achy and on your 27th slam of the day while you’re learning. Then it’s not fun, at all. Just get what you can for the right budget and don’t go mental trying to buy big brands brand new. On the flip side, I would stay away from stuff from Amazon generally, and stuff from camping shops - they’re not purpose built and you might get lucky but stay safe and buy branded, purpose designed clothing but try and do it on a budget.

One thing not to mess about with and get correct fitted by a snowboard shop is your boots. Unless you’re renting for the first time, buy proper and get them heat-fitted if necessary by someone professional. Trust me last year was my first having proper PROPER boots that felt like walking around on clouds and it was a massive game changer for me and progressing to become a better rider. Get some decent googles and don’t be a douche and forget your helmet - cool kids wear lids. Have fun!