Can we still use SharePoint designer with SharePoint Online in 2021?

jcgonzalezmartin 

True but I can do so much more using designer.  I don't use it for workflows anyhow. I mainly use it to design my pages and use my JavaScript the way I want it and not the backend of the box style.  Microsoft always seems to find a way to break backend work. So, I push things into SitePages for use and it never breaks. I also use W3 CSS for a more functional look and feel. The classes I use are not Microsoft related and that gives me an edge to a clean quick design rather than fiddling with SPFx that is problematic and you need to be a rocket scientist to make it work. NodeJS errors on just about everything I have been told to do even with 1.20. The whole point of SPFx was no to low code design and it is neither. A modern page doesn't go back to 2003 Team Foundation server to make work.  It improves on what is already in place. If Microsoft had made an update to SharePoint Designer and removed workflows from the design, I could go wild. They removed Creating forms because of PowerApps which is mediocre at best. You still have to do a bunch of code I never had to do with Designer because it was built in. I am still wondering why people thing SPFx is so good. It drives me nuts at every corner. 

jcgonzalezmartin 

Actually SharePoint Designer is a better and easier tool to use to develop premium sites that can use W3 tools to display amazing dynamic content using lists that you develop in SharePoint that include document libraries. You can design responsive pages using W3 components unlike the modern interface that forces you to code so much more. Even though it's called low code it's actually double code. Since all of the code is SPFx collecting information easily has gone away. The complexity of the modern interface almost forces people to go back to school to relearn new and overly complicated methodology. By simply turning on SharePoint Designer you can have a much more intuitive site that can work like your business rather than being forced to do things another way.

As for workflows I would use Power Automate it is the best tool at the moment even though you have to do a little coding and know some nuances. There is plenty of helpful information on how to.  The nice part is this is the only tool that I like about the modern stuff.