Jumping into Web Development

Mainly worked with Android Studio, competent in Java with very light experience in Spring Boot.

Need to ship a twofold product over the next few months which is my main motivation. First part is a simple stand alone web app targeted at a small audience, followed by a marketplace platform (mobile & web).

What stack & tools do you recommend? I'm trying to optimize for speed over any other factor.

A route that was suggested to me is a combination of React & Spring Boot, but I don't feel it's the quickest path and wanted to get some sound advice on this.

Recommended resources are greatly appreciated as well.