I've bounced around Splunk, New Relic, Sentry and Datadog over the years. Most recently, I was working with Java and used the open source Vendor-neutral application observability facade Micrometer[1] to test out and confirm which APM we wanted to go with.
You should also check out SigNoz [1]. It's an open source observability platform with metrics, traces and logs in a single application & based natively on opentelemetry.
One of the reasons many people use SigNoz is to avoid the vendor lock-in which comes with adding proprietary SDKs of closed source products like DataDog and New Relic in their code.
If anyone is starting their observability journey today, I think OpenTelemetry is a very good place to start. You can instrument with Otel SDKs and chose a visualization layer/backend which suits your needs best
(Disclaimer: I am maintainer at SigNoz)