I recently brought one of my 5e characters from Beyond into a 5.5e game. It was my first time using the 2024 rules, so I was learning the new system as I went along. When I looked closer at specific rules and compared options that might've changed for my character, I realized just how different 2024 actually was from the 2014 rules. More importantly, I realized that the people at the table (including the DM) hadn't even noticed until i started pointing them out.
Was it an issue? Not really, unless you're someone like me who just prefers things to be clean, simple, and neat. Once I understood why changes were made and the intent behind them, I could no longer ignore them. Things worked different (and better IMO) for a reason.
For example, I learned that the Observant feat no longer gave my character a +5 bonus to passive Perception and Investigation checks. That was a schtick for my character, but I could see how the change improved play at the table by curtailing an (admittedly) annoying and frustrating aspect under the original rules. Instead, he could get Expertise in one of those skills, and use Search as a bonus action.
Of course, this would still be a good choice if the group was actually following the new rules to use the new Search (and other) actions correctly. As it turned out, they had glossed over the new rules (except the crunchy bits that interested them, like character classes, spells, etc), and assumed everything worked exacrly the same as before.
My "practical advice" is this: You can do whatever you like. Just be aware that "compatibility" doesn't mean "frictionless". Be prepared to make compromises, adapt on the fly, or just outright ignore things that aren't improtant to the group. It's easier not to overthink it, and just go with the flow.
But if it matters to you, or anyone else at the table, consider that 2024 attempts to address and improve many of the problematic issues people have complained about (and dealt with) for years. Allowing old options to come back is potentially inviting those same issues back. Which begs the question, why not just keep using the old rules instead?
Just food for thought.