As someone interested in cryptography, I'd also recommend a VDF. A Wesolowski VDF isn't that hard to hand-roll [0] [1] and will make parallel attacks much harder while penalizing low-power devices less.

[0] https://reading.supply/@whyrusleeping/a-vdf-explainer-5S6Ect [1] https://eprint.iacr.org/2018/623