We do not provide full TXT record management with our hosting. You can setup SPF records through our panel, but that’s it. If you want more DNS controls, you can use external nameservers for your domain name. This guide to Cloudflare may be helpful to you: A Full Guide To Cloudflare
Setting MX records is done like so: How to set MX records on your domain
However, please note that an MX record is not the same as an email forwarder, and cannot be used to just forward everything to a Gmail account. If that’s what you want, you could either choose Google Workspace, which is like Gmail but for your own domain (but quite pricey), or just use a (free) email forwarding service like ImprovMX or Cloudflare Email Routing to forward the mail to your Gmail account.