The American system is very different to ours and places far more power in the hands of the President than our system permits.
The US president is voted into office by the electorate and once there has wide powers and discretion to make major decisions without needing the support and approval of either Senate or the House of Reprsentatives.
Apart from the dreadful decisions that Trump made, look at the way Biden has been able to complete over ride many of the policy decisions thatTrump made without needing any support and approval from the legislature
These are way beyond the powers any British Prime Minister has. Here we vote for our MPs and the winning party's leader becomes PM, who can be dismissed by his party at any time and, except in a very limited way, all legislation has to get Parliamentary approval