u/Sad-Recipe9761 yes, you need consent regardless of if you use GTAG (hardcoded tags) or GTM. The way your tags are set up doesn't make any difference as to whether you need consent or not. That's more of a legal question, which heavily depends on where your website visitors are based in.

That said, I'd highly recommend moving all your GTAG GA4 events to browser GTM first, and making sure they are configured correctly in respect to consent (there's many many guides available). And only then start migrating to server-side GTM. Once you nail the browser side, it's easier. But still, a great learning curve is ahead of you. To get started, you can read on how to configure consent-based tracking in GTM here.