Can anyone advise is it good for 5700xt or can further improve more hashrate, the power draw is around 133W.
ZelHash algorithm is a Flux coin ?
https://www.hashrate.no/gpus/5700xt/FLUXCalculators don't always give correct hash rate values because miners are constantly optimised, but I think you are close to the upper limit of hash rate. Sometimes it's not a good idea to mine at maximum power consumption.
If the calculator doesn't lie, the most profitable algorithm for this video card right now is kawpow.