Speed too low, even if the engine is still running?

Hello to each other, I used to drive a Yaris XP9 1.33 VVTi suction cup, meanwhile switched to a Fabia 3 1L TSI. The car is very quiet even in the low speed range. I seem to be able to drive easily in the 4th gear at Tempomat 43 and in the 5th at 53 with approx. 1200 rpm with relatively flat road up to very easy ascent. My Yaris would have been buzzing like crazy with the speed at that time. Can of course also be due to the today’s low mileage. , Is it healthy to drive the engine like this or should I rather go down a gear to 1500-1600 rpm? Of course I don’t always drive like this, once a week I’m also on the highway. Thanks for your informed opinion.