I understand the game is free with some DLC’s and I’ll suggest first to offer 1 additional shop slot and 1 additional warehouse slot for in game credits.
Then offer warehouse space up to 10-20 via purchases.
Then offer ship slots up to 20 via purchases.
These 2 are separate from the Supporter DLC you have.
Continued Funding Suggestion
Remove the game from Early Access. People have been burned too many times to believe in EA.
Decide some things you want to add to the game. Let’s say an expansion to bring in new systems, new ships (now you can understand my additional expansion above), new cosmetics for said ships, maybe redo the new user experience.
Take that and create a campaign on Kickstarter asking for the funds you think it’ll take to get it in game.
If possible add some holiday events with holiday specific cosmetic drops but then you include paid cosmetic versions too. The best idea is to never put all the cosmetics behind a paywall (look what happened to Destiny 2).