Are any IR35 rules relevant to you?
These 2017 and 2020 changes to how IR35 operates only impact on any case where IR35 is relevant, i.e. where a PSC is involved. If a freelancer does not work through a PSC but through some other type of entity (e.g. an agency or managed service company), then other rules will or might apply, so it is important to understand what amounts to a PSC for the purposes of IR35.
So, if you engage a freelancer working for you directly as opposed to working through a PSC, you will not be affected by IR35.
However, as a consequence of normal tax law (not IR35 rules) applicable in these cases, you will still need to decide whether they are an employee rather than a sole trader or contractor. If they are an employee, you will have to operate PAYE.