LTM monitor option to do the health check of the servers based on its performance

The easiest options would be to select ‘Fastest’ load balancing method. The theory is servers that are more overloaded will have a slower response time, so a smaller ratio of connections will go to these servers.

If you want to perform an advance health check you would need to discuss this with your application team, with them perhaps writing a dedicated web method that F5 could check performance

I once worked at a place that wrote a method that allowed an API call trigger a DB query, a successful response proved the full application stack was working.

You could use a similar approach to only return a successful response if the server is within certain performance thresholds such as having less than 50% CPU utilisation.

Another alternative would be to use an external monitor to query the pool member via SNMP to return performance metrics.