As per the message " There is already an object named 'ShippingByWeightByTotalRecord' in the database."
The plugin seems to be already installed, but the plugins.json table does seem to have it.
You could edit this \App_Data\plugins.json, and add this
"Shipping.FixedByWeightByTotal",
after this line
"InstalledPluginNames": [
But, it might be safer for you to use a SQL client tool like SSMS, and delete/drop table ShippingByWeightByTotalRecord
And then try the Install again.