dell does not publish acoustic noise tech data after optiplex 790.  in general if you get an optiplex with ssd, no hdd/odd (i.e., no mechanical spinning drive), relatively new Intel gen cpu with lower TDP (65W or less), and SFF format, it is more quiet.

for your reference look up 790 tech guide for acoustic data.

Opti 790 Tech Guidebook v2.1.pub (dell.com)

790 has 2nd gen intel cpu, which has higher TDP (95W) than 6/7/8th gen.  this means cpu fan has to work a bit harder to keep it cool assuming same heatsink/thermal paste.

Quiet is a relative term.

For your requirements I would say this model.

https://www.amazon.com/Dell-Optiplex-7010-SFF-Desktop/dp/B01HSDJFFM

I’m thinking of getting the 3060mff as the tdp very low(35w), thoughts, do you think it will be quiet? 

as the 7010 has a high tdp I think it might be better to avoid.

thoughts? As the 7010 had a 3470 which is 77tdp.

I would avoid tiny micro pc for these reasons: tiny chassis not great for air flow, which is why they have to use very low TDP cpu.  fans are tiny in micro, so they have to spin faster to move same amt of air per min.  faster spinning entails greater noise.  these limitations defeat the purpose of quiet fan.  somewhere between tower and micro may be better balance.  you can custom config the SFF to have the 35W TDP cpu too if you want.

I5-8500 in a 3060 SFF is only 65w.  Any of the PC's suggested and the 3060 SFF will run quiet under everyday loads.  You'd have to try gaming on them, or use other CPU heavy apps, to get the fans excited.

For now, avoid the 3080 SFF until Dell gets its ticking problem worked out.  3080 more expensive anyway.

"790 has 2nd gen intel cpu, which has higher TDP (95W) than 6/7/8th gen.  this means cpu fan has to work a bit harder to keep it cool assuming same heatsink/thermal paste."

I3-2100 is 65w.  But the 790 doesn't have USB 3.0.  The 7010 does.  My 790 DT runs silent.  So did my 7010 MT before I added fans, but the little fan noise isn't noticeable.

I too agree to avoid micros.  In addition to reasons listed, some can easily come off as under-powered (unless they have a good PSU) - not even enough to run however many USB slots it has.

One more thing I wanted to add:  TDP's for CPU's is their max, not what they're at while idling or lighter loads like internet browsing and Word.doc.