For HTTP/HTTPS apps, as long as you select Allow/Allow on the policy, vs Allow access with restrictions, you can access SPA apps on client native browser (from a user experience pov, it's like ACVPN on a cloud gateway).
CSA will come into play if it's configured as a TCP/UDP app, but also may be pulled in if the above mentioned web app has session pol/routing rules configured like a web app with printing enabled.
Note about the above policies... in my experience the wizard that builds these rules area you better get it right, and you can't edit it, deal.
eg. If you initially select "Allow with Restrictions", and then select something like "Clipboard disabled", that will force them to use CEB/Chrome Enterprise. If you later decide you want to allow the users to use Native Browser, you can't just uncheck the box and select "Allow Access". Instead you must delete the policy and create a new policy as desired.