So I just got my MacBook Air m1 and tried to hook it up to my old monitor a Philips 243v (a very cheap monitor) I went out and bought a usb-c to DisplayPort cable but my Mac won't recognise it and my screen displays "no signal" (DisplayPort) ? Was looking at the Dell S2721QS and was wondering if anyone else has the same setup and can tell me if they have any connection issues ?
You should be working with an USB type-c to HDMI active adapter for your setup.
If you intend to use to the USB type-C to DP cable, which you currently have, it should work with the Dell monitor you've listed at the end of your post. Mind you, it's a good idea to parse a link to the cable you purchased for a once over by the community.