I was used to focus most of my stays at the same group in the same year. From my point of view the best status was the Royal Ambassador at Intercontinental hotels. But that time is gone. Now I think the best strategy is not to waste too much time in caring about hotel programs. It's better to get some status, which are easy to get without stays or nights. Having a lot of stays and nights to get a high status at 1 hotel group makes only sense, if that hotel group and its status really cover your locations and needs. For most of us that 1 hotel group doesn't exist.
The best way to stay at IHG is buying the Ambassador, which includes IHG Platinum (USD 200/year). Spire or Royal Ambassador don't make sense any more.
The best way to stay at Hilton group for US citizens is to get Diamond status with the AMEX aspire (USD 450/year). But Gold is quite good already and it comes with a lot of other cards/programs for little money.
I'm not a Marriott Bonvoy expert, but I know, that Amex offers a credit card for US citizens, where you get Platinum Elite status (USD 450/year plus USD 75k a year in spending). Maybe others know an easy way to get Bonvoy Platinum, which is from my point of view a good status.
So my budget recommendation is to buy the Ambassador and to get Hilton Honor Gold from somewhere. If you want to spend more money, buy the Ambassador and get the Amex aspire. If money doesn't matter, get the Amex Platinum and spend a lot of money to get invited to the Amex Centurion.
Watch out for other ways to get a good accommodation without a status, like FHR/Amex, Impresario, Airbnb, etc. From my experience girlfriends and wifes appreciate the freedom to choose the best hotel for a stay. It's more romantic than staying for status/points/benefits.