There is growing interest in Treasury FRNs. These didn’t do much during the ZIRP, 2020-22, but have done well after 2022 as interest rates rose.
The 2-yr Treasury FRNs pay the yield of 3-mo T-Bills (reset weekly) plus spread (set at the Auction). The interest accrues daily but is paid quarterly. These require less frequent rolling than 3-mo T-Bills. Auctions (original issue or reopening) are monthly. Among the brokers, Schwab accepts online orders, but you will have to call Fidelity’s fixed-income desk to enter Auction or secondary market orders. www.treasurydirect.gov/marketable-securities/floating-rate-notes/