DIDs are rooted in ECDSA keys (secp256k1). Each user identity is a non-PQ cryptographic commitment. These ecosystems must start migrating very soon because if CRQCs arrive before they're done, they face a choice between user compromise and bricking accounts.
I've been writing notes on Heroku alternatives (mostly Fly, Railway, Render) at https://croaky-webstack.deno.dev/ Maybe something useful in there for others.