[ilyt]

Is orange pi 5 as fast as 35W TDP intel CPU ? How many times slower it is than the 65W one ?

Average consumption matters, not peak. And you can pin CPU to not go on higher frequencies if you don't want to go into inefficient max frequency/max voltage region.

You will also be recycling already produced device.

[arghwhat]

According to Geekbench, an i5-8500T scores ~1100 single core, ~4000 multicore with it's 35W TDP, while the Orange Pi 5 gets ~840 single core and ~2900 multicore. About 75% of the performance at less than 20% of the power. Not too shabby, despite the orange pi being no efficiency star.

Recycling is good, but only to a point. At some point the cost of operation (and resource pressure from its use) will exceed the cost of a more efficient device - at least until we get abundant green power...