I'd recommend using gold to build ideas for adventures, as Prakriti put it, in the AD&D days you used all that gold (and you got a LOT) for things like strongholds, paying followers, bribing guilds, buying treasure maps, installing teleport circles in your Tower, and so on, which led to more adventures. There's a great DMGuild item,
Balduran's Guide to Kingdom Building, if you're looking the stronghold route.
3rd Edition, imo, mucked it up a bit by introducing a maligned concept called "wealth by level," which led to the magic shop and magic item factory characters. However, the idea of buying magical items has been around since the AD&D days (they introduced gold piece value for many items). This didn't mean you got on Amazon and bought a vorpal sword for 100,000 gold. It reflected the price it might take for someone to be willing to part with that item if you could find such a person.
Rather than let people shop, let players purchase a scroll that takes them to an astral facility where they can meet the Architect, who is said to have knowledge to craft all things, and is willing to send them on a quest, perhaps through space and time to salvage something lost, rewarding them with a formula to create a magical item only known in legend (such as the Staff of Power). From there, quests can be had to find the ultra-rare ingredients (perhaps one is a busted staff, known in sealed documents to only exist in the Abyss where it was broken by the Archmage Plot Device while facing down the demon lord So and So.)
This way, your gold leads to adventures, not the "ye old magick shoppe," while still providing access to magical items in a meaningful way.