You're not "doing SMURF". It's not an approach or a system. It's just a specific vocabulary to talk about testing approaches better. They almost spell it out: "The SMURF mnemonic is an easy way to remember the tradeoffs to consider when balancing your test suite".

It's up to your team (and really always has been) to decide what works best for that project. You get to talk about tradeoffs and what's worth doing.