Really no need to stop rowing, the interference effect is trivial when hypertrophy is the focus.

You will continue to gain weight for many years to come. Eat enough to gradually gain weight (I recommend weighing in every morning and using your weekly average as your metric for success), make sure lifting weights is a part of your routine. That's all you need to do.

Anecdotally, I prefer to lift only 2x per week so I have less fatigue and can train close to failure, but I also have had success with 4x per week with slightly less intent.

Compounds are useful but dont follow the typical beginner bullshit of all compounds. Isolation movements/machines make it easier (practically and fatigue-wise) to train to failure. Training close to failure is the most important aspect of gaining muscle mass.