Exhaust Pressure Sensors
 

Modern cars have these, they seem to go in the EGR cooler, so one would still need to have something to keep it cooler than 900c
i'm sure these are well known, but it was news to me!

Mazda's sensor is PYAH-18-211A found on the 2.5 Turbo engine, so 2016+ Cx9, Cx5, CX30 etc
Mazda says "A piezoelectric element is a resistor element which produces voltage by the application of vibration or pressure. Using this characteristic, the piezoelectric element detects exhaust gas pressure as voltage."

Mopar has 68002442AA which looks like a better choice. Used on the 2011+ Ram Diesels
https://cimg3.ibsrv.net/gimg/www.rx7...12051df1cc.jpg

and BMW has 13 62 8 507 634, which has a hose barb, so it might be the easiest to install
it looks like the car has a banjo fitting to a pipe to a hose. it fits the 2014-2018 3.0 Diesel x3,x5, etc
https://cimg2.ibsrv.net/gimg/www.rx7...3a8f0e3575.jpg
https://cimg4.ibsrv.net/gimg/www.rx7...d27f7c110b.jpg

it looks like the Mazda Diesel uses something similar to the BMW, SH09-18-211