You have a hardware issue.

And, unfortunately, it's a logic board problem.

• The power rail not may not be delivering enough current to the USB bus
• The USB controller for that side may be malfunctioning
• The circuitry that connects the controller to the port may be problematic.

Unfortunately, without putting hands on with proper diagnostic gear it's impossible to know. In fact, if you take it to Apple, they will simply change out the logic board rather than identify and fix the problem.

The one thing you should do is an reset the SMC. There are different methods depending on your Mac model so be sure to read the steps carefully.

This is one of the actual few problems where an SMC reset is applicable - you're having power issues. Re-installing macOS is the last thing you should do - booting into Safe Mode or Recovery will get you a clean version of macOS without the hassle of overwriting your system and risking your data. You can also run Apple Diagnostics to see if there are any error codes.

You have a hardware issue.

And, unfortunately, it's a logic board problem.

• The power rail not may not be delivering enough current to the USB bus
• The USB controller for that side may be malfunctioning
• The circuitry that connects the controller to the port may be problematic.

Unfortunately, without putting hands on with proper diagnostic gear it's impossible to know. In fact, if you take it to Apple, they will simply change out the logic board rather than identify and fix the problem.

The one thing you should do is an reset the SMC. There are different methods depending on your Mac model so be sure to read the steps carefully.

This is one of the actual few problems where an SMC reset is applicable - you're having power issues. Re-installing macOS is the last thing you should do - booting into Safe Mode or Recovery will get you a clean version of macOS without the hassle of overwriting your system and risking your data. You can also run Apple Diagnostics to see if there are any error codes.

Potential Workaround

If you can still transfer data, just not handle the "strenuous" tasks as you described, you may still be able to work with it if you use a powered USB hub. It will supply the power to the USB bus that your logic board can't

You have a hardware issue.

And, unfortunately, it's a logic board problem.

• The power rail not may not be delivering enough current to the USB bus
• The USB controller for that side may be malfunctioning
• The circuitry that connects the controller to the port may be problematic.

Unfortunately, without putting hands on with proper diagnostic gear it's impossible to know. In fact, if you take it to Apple, they will simply change out the logic board rather than identify and fix the problem.

The one thing you should do is an SMC reset. This is one of the actual few problems where an SMC reset is applicable - you're having power issues. Re-installing macOS is the last thing you should do - booting into Safe Mode or Recovery will get you a clean version of macOS without the hassle of overwriting your system and risking your data.

You have a hardware issue.

And, unfortunately, it's a logic board problem.

• The power rail not may not be delivering enough current to the USB bus
• The USB controller for that side may be malfunctioning
• The circuitry that connects the controller to the port may be problematic.

Unfortunately, without putting hands on with proper diagnostic gear it's impossible to know. In fact, if you take it to Apple, they will simply change out the logic board rather than identify and fix the problem.

The one thing you should do is an reset the SMC. There are different methods depending on your Mac model so be sure to read the steps carefully.

This is one of the actual few problems where an SMC reset is applicable - you're having power issues. Re-installing macOS is the last thing you should do - booting into Safe Mode or Recovery will get you a clean version of macOS without the hassle of overwriting your system and risking your data. You can also run Apple Diagnostics to see if there are any error codes.