Try these methods depending on how much time you can give, How much priority do you have for this account and how much budget/time are you willing to spend on the account :
1.Manual F/UF - Either you can do this on your own, You can hire a VA or you can get a service to do it for you. As far as the limits are properly taken care of, There is nothing you need to worry about.
2.Mother Child - This is expensive or takes a lot of resources but you need authority account to get the best results possible, Newer accounts don't work good with this one.
3.Mass Dm's - Expensive if not played right, Still needs some authority to get the best results possible.
4.Consistent Posting with Trending and High-Quality Reels - This is organic and can give you a free boost if you get lucky, But we never know when IG would stop giving you an organic boost all of a sudden.
Key is to try multiple methods and see what works for you, Completely depends on your situation.