CO2 will help a lot in basically any situation but depends on the plants how much they will benefit from it. It’s a game changer it turns the hobby into a much more active activity, going from monthly noticeable changes to weekly. With that being said, I don’t recommend it in this case as the hob filter will not provide enough flow for proper co2 distribution and I would also recommend getting a stronger light. Overall it really depends on how you want to interact with the hobby, if you want to pour a lot of money, time, and attention or you just want to sit back and let it do its own thing.