Is it the Helix framework you are concerned about or SP Pagebuilder?

There are no known issues with the Helix Framework/Helix Ultimate Template - you should remember to create Bootstrap 4 based layouts in EasyLayouts since the Helix Ultimate template is based on Bootstrap 4.

SP Pagebuilder is more problematic - if you were hoping that EasyLayouts could customise the output of the articles addon (for example). This isn't possible at present, since SPPageBuilder has hard coded the output of the articles addon. It MAY be possible for EasyLayouts to override this if its important to your requirements.

Just created an account to ask this question.. didn't see it before. So no problems with helix ultimate with bootstrap4. Thats good.

SP pagebuilder and easy layouts together makes no sense I guess .. So no problem it doesnot work with pagebuilder

As I said it may well be possible to override the output of the SP Page Builder articles layout is that is an important feature for you,