Monero transactions offer the most cost and space-efficient transactions, at 1,419b in size with a median cost of $0.056, support the most Bitcoin-weighted TPS when comparing “reasonably private” spends with 2min blocks and an initial median of 300KB and a hard cap of 2x median, and lowest chain growth of 0.46GB/d. Monero has significantly shown to scale better than every other alternative as transactions [0] and adoption, notably dark market adoption [1] continue to increase.

All data is available at https://sethforprivacy.com/posts/comparing-private-spends/#results
[0]: https://moneroj.net/translog/
[1]: https://moneroj.net/dread_subscribers/