It is said that “You can’t upgrade directly to version 26 from version 24 or earlier because version 26 deletes many objects. Upgrade to version 25 first.” (Upgrading Microsoft System and Base Application to Version 26 - Business Central | Microsoft Learn)
But I tried to upgrade directly and I don’t see any issues with that.
I understand that from older versions that could cause some problems, because removed fields might be not copied to new fields. But I checked upgrade procedures on BC25 and BC26 and they are not changed - all existing on BC25 exist on BC26.
Maybe somebody knows what is real reason for this requirement?
I still remember way back in 2021 when I did my first upgrade to BC from NAV Version. V 14 is mandatory as its a hybrid modal but later on I have also skipped few versions and landed on the one I wanted. Fortunately I never ended with any issues but still I will recommend to follow Microsoft Documentations. 
I am 99% sure that Microsoft originally said this would fail and then changed their minds and adjusted it so that BC 27 will introduce the changes. I’ve had a few customers upgrade from BC 14 to newer versions lately and they’ve worked (not sure if we tried v26 but def v25 works from BC14 still).
Try it in a sandbox and check your Trial Balances and other Subledger reports and see if they match.
If you don’t mind objects that should be deleted sticking around because you bypassed the version that runs the cleanup scripts, then I guess you’ll be fine. But there’s no telling what else might go wrong, so why risk it?