It's unlikely that a 5G cell phone signal booster will directly boost your internet speed. While it may improve your signal strength, other factors play a much bigger role in determining your internet speed. 

The reasons are as below:

What Boosters Do:

Cell phone signal boosters amplify the existing signal from cell towers, improving call quality and reducing dropped calls in areas with weak reception.

They don't increase the bandwidth available from the cell tower itself.

What Affects Internet Speed:

Network congestion: Even with a strong signal, if the cell tower is overloaded with users, your internet speed will be slow.

Your data plan: Different data plans have different speed limits. Check your plan details to see what speed you're paying for.

Distance from the tower: The further you are from the cell tower, the weaker the signal and potentially slower the speed.

Alternatives for improving internet speed:

Upgrade your data plan: Consider a plan with a higher speed limit.

Connect to Wi-Fi: If available, a strong Wi-Fi connection will typically be much faster than cellular data.

Contact your provider: If you're consistently experiencing slow speeds, contact your mobile carrier to check for network issues or upgrade options.

Additionally:

Overall, a cell phone signal booster might improve your signal strength, we also need to consider the reasons above.

Cell phone signal booster is amplify the signal picked up from the cell towers, but it can not generate the signal itself.  Once the cell phone signal is improved, the cell phone internet speed might be improved also.