The right replacement depends on which job you used TweetDeck for in the first place.
The column client that people used for years was folded into a paid tier with a narrower feature set. That left two groups: people who want to read several timelines at once, and people who were quietly using it to run a handful of accounts.
Column clients are for reading: keyword columns, lists, monitoring. Management workbenches are for operations: many accounts, per-account isolation, publishing queues and inbound DMs.
If your real need is the second, replacing columns with different columns keeps the same ceiling.
Account isolation (one fingerprint and egress per account), write rate control, whether it uses the official API, DM handling, and how it is deployed. Run the same five questions against every option and the choice usually makes itself.
For several accounts with inbound DMs, the bottleneck is answering, not reading. A desk workflow — assignment, status, shared history — saves more time than any number of columns.
There are community and open-source clients, but expect maintenance gaps and limited multi-account isolation — fine for reading, risky for running accounts.
Lists remain the cheapest way to follow many sources from one account. They do not solve multi-account operations.
Decide first whether you are reading or operating. Every recommendation after that follows from one of those two answers.
The right replacement depends on which job you used TweetDeck for in the first place.