I plan to build a Chrome extension and am considering making it paid, around $2 for lifetime access. Also Desktop app is also good idea

Extensions have the downside that a malicious actor can buy out the original dev and start using them as an intrusion point.

Don’t make either unless you have the resources to support them. Anything paid is also a business process with tax implications.

Local-only web apps are great one-off projects, but extensions and native apps require much more maintenance.

Make the Desktop Version natively, even tho its time efficient to make it just Electron