Explova Nosa S direct trainer

Hi, I am new to Zwift and wonder if anyone else is using the Explova Nosa S direct trainer?

I read the post about common things new racers do/think and I am possibly guilty of thinking my power output is not corresponding to real life. This is because I race against members of my cycle club, who I know well and I can keep up with them fine on the road in RL, but I am toasted after the first 5km and they end up gaining about 15 mins in an hour race.

I have done an FTP test which admittedly came up lower than my spinning results last year, but I have had pneumonia in between those so that is not surprising.

I realise that riders on dumb trainers might have estimated inaccurate power but I am concerned my trainer of or my heart rate are not giving the right results.

How can I check?