There is a really good reason why the EU stepped in on vacuum cleaners as it started to become all about wattages and not about actual cleaning performance. Cleaners were being built with stupidly high wattages primarily due to stupid bagless designs that either wasted a lot of airflow on multiple cyclones or needed the extra power as the dust separation was so poor that the filters clogged near instantly.
Vacuums only really started having 1000w+ motors in the late 80's and even then it was generally only cylinder vacuums that had the extra power as they generally had no assistance from a rotating brush roll for carpets.
A modern Henry/Hetty with it's 620w motor compared to the previous 1.2kW motor has very little difference in suction as they've done more than just fit a lower wattage motor, plus if you really wanted a 1.2kW model then there are plenty on the 2nd hand market that will last for years. My Gran's 800W Henry is from 1987 and yet not only still works fine it also has more than enough suction power.
Personally a vacuum such as an 620W Henry (for primarily hard floor, thin carpet, or carpet where a rotating brush roll is not recommended) or for carpets a SEBO Felix (700w suction + 120w? for the ET-1 powerhead) will probably clean better than any 1kW+ vacuum, esp. if it a far eastern bagless one.