what are the limitations of OOTB SP forms against InfoPath forms?
can we create multiple views on the same list using OOTB forms? how about rules, change the width height etc.
The InfoPath form surpasses the default SharePoint form in the following:
Can we create multiple views on the same list using OOTB forms?
How about rules?
Change the width height?
[Update based on comment]
PowerApps and Microsoft Flow are the successors to InfoPath and SharePoint Designer for many common business scenarios, especially custom forms used in SharePoint lists.
OOTB is what you see is what you get. You can configure the forms if you want in SPD (SharePoint designer) to have what you want in the forms like you suggest. or directly edit it which i dont suggest ;)
do you mean multiple forms like edit, add? or views of the list?
as for infopath yes it can do a lot more than OOTB but its being phased out so why use it? You should be embracing "Forms" / "PowerApps" and "Flow", these newish 365 applications should be used to create new forms and workflows. You could still use SPD for now or keep on using it as i dont think its going any time soon. Because both apps are still new they wont have full functionality but should be able do what you want.