Ads first — no question. SEO takes 6-12 months minimum to tell you anything useful. Ads tell you in 7 days whether your offer converts. That's the only data that matters before you invest in anything long-term.
On your suspension question from earlier in the thread: the "banned for no reason" thing almost always has a reason, people just don't know what triggered it. The three most common ones I've seen:
1. Fresh account + big budget launch. Google's systems flag unusual spend spikes on new accounts. Start at $5-10/day, let the first billing cycle complete cleanly, then scale.
2. Landing page mismatch. If your ad says one thing and the landing page says another, or you have thin content with aggressive claims, automated review catches it fast. Make the page clean, no misleading language, real contact info visible.
3. Payment method issues. new card on a new account with no billing history gets extra scrutiny. if you have an aged account with existing billing history, use that for early tests.
For your actual question best first step: pick 5-10 exact match keywords, write 2-3 ads per group, send to a focused landing page, run for 7 days at $10/day. If you get clicks but no conversions, the LP is the problem. If you get no clicks, the keywords are wrong or the bids are too low. Either way you have a real signal instead of a guess.
SEO is still worth building in parallel, just don't expect it to be your validation tool. AI search is changing rankings faster than most SEO plays can adapt anyway.