Just now I checked a few on-chain swaps and feel like many people treat "sandwich attacks" and "arbitrage" as opportunities. Honestly, you might think you're making money, but you could just be helping others collect fees and slippage... I'm actually more afraid of those transactions that go through too smoothly, too perfectly, as if someone is lining up behind and in front of you.

Low frequency trading has its advantage—taking it slow. I'd rather miss out on that quick profit than risk it. No rush; waking up later is fine.

Also, recently the testnet incentives and points have heated up again. People in the group keep asking if the mainnet will issue tokens. I don't know either. Anyway, I'm more concerned about not turning myself into "predictable traffic" just for points.
You ask, "How do I tell if I've been front-run?"... I usually just reduce my trade size or simply stop chasing. That's it for now.