Maybe a consumer thin mini-itx with 35W power limit on PCI-E and z390 chipset for downclocking/downvolting? To make a 9900T from 9900K.
Most thinITX has PCI-E x4 with 25W PL.
Although, i3-4130T + GA-H87TN + GT1030() works fine in my fanless system since 2017.
So, my staff was...