I’ve been playing a Les Paul through Amplitube on a laptop and headphones, primarily using the Brit8000 amp, and have been quite satisfied with the tones I’m able to achieve.

I want something that will let me get ‘bedroom’ level volumes (with good tone), without headphones and was considering a combo amp such as a Marshall DSL40c or possibly a Blackstar HT40.

My other option is to continue to use Amplitube but get some studio monitors, considering the Yamaha HS8’s.

This will just be for solo practice, not intended to play with others.

I’d be interested in experiences and pros and cons of both.
Nothing beats a real tube amp but in your case I wonder how much volume you can achieve without the neighbors complaining.
I'd say go for the DSL40C but test it out first to make sure it isn't too loud for you. If you want to record you'd have to mic it up.

Modeler - never gets quite there as real tube amp but you have more sound options, say Soldano models, Mesa, etc. Easy to record but IMO harder to mix with than real amp.

I wouldn't go for HS8s for your needs if all you're looking to play, I'd say $200-$350 monitors will do just as well. Maudio Bx5a is a good option, some JBLs, Eeris, etc.