I’ve got some basic dumbbells through amazon (might have been ebay). 2 x (3kg, 5kg, 8kg, 10kg) . Think they were about £140 at end 2019.
Great for a wide variety of stuff. As above consistency and variety is key. Also keeping it fun.
Only thing I’m missing out on is larger weights for big compound moves like squats – but i am finding that bodyweight moves and using a different technique with these dumbbells can be adjusted to make them harder if required – e.g. squats can be made harder by doing them with heels off the ground, or by more reps, or by less rests between reps
Those Nino workouts are excellent as well – one for the garden gym in the spring.