What is the best platform for tracking website performance metrics?

I’m pretty new to this. I’m helping a friend with one or two sites and just trying to figure out the best tool for monitoring uptime, response times, alerts… basically the basics. Downtime = frustrated users (and lost money for them), so I need something reliable but not overly complicated, and ideally something that doesn’t drown me in false alerts.

Looking at G2 reviews for website monitoring tools, a bunch of platforms stand out:

• UptimeRobot: simple and reliable, seems like a go-to for beginners.
• Site24x7: broader monitoring (websites + infra),.
• Better Stack: clean dashboards and alerting, looks good for incident tracking.
• Dynatrace: enterprise-level, probably overkill for a small setup but looks very feature rich.
• LogicMonitor: same deal as Dynatrace, seems aimed at larger infra.
• Pulsetic: uptime checks + status pages, seems easy to get started.
• Freshping by Freshworks: straightforward uptime monitoring, part of the Freshworks suite.

Outside of this list, I’ve also seen people mention Pingdom, Datadog, and New Relic a lot.

For someone like me (novice, small setup), what would you recommend? Should I just start with something simple like UptimeRobot or Pulsetic, or is it worth jumping into a more full-stack tool early on?