Why do I have to reload this plugin every time, to make it work?

I’m not "fluent" in PyQGIS but thanks to some tutorials I managed to put togheter a plugin that acquires the clicked point’s coordinates and saves a QRcode containing the link to google maps for that point.
The plugin works fine but it needs to be reloaded every time because when I swich to other tasks (like selecting elements) and then come back to the plugin my mouse pointer doesn’t change shape to a cross as it should, so I think that there is some problem with the command QgsMapToolEmitPoint(canvas) .
This is a snippet

from pyproj import Proj, transform
from qgis.core import QgsProject, Qgis
from qgis.utils import iface
from qgis.gui import QgsMapToolEmitPoint
import qrcode
from pathlib import Path
epsg=32632

    def display_point( pointTool ): 
        
        #print(epsg)
        
        inProj = Proj(init='epsg:%s'%epsg)
        outProj = Proj(init='epsg:4326')
        x1,y1 = pointTool[0],pointTool[1]
        x2,y2 = transform(inProj,outProj,x1,y1)

        #creates folder QR if doesn't exist
        Path(QgsProject.instance().readPath("./")+'/QR').mkdir(parents=True, exist_ok=True)
                
        img = qrcode.make('https://www.google.com/maps?q=%f,%f' %(y2,x2))
        img.save(QgsProject.instance().readPath("./")+'/QR/%f,%f.png' %(y2,x2))
        
        link = 'https://www.google.com/maps?q=%f,%f' %(y2,x2)
        path = QgsProject.instance().readPath("./")+'/QR'
        
        iface.messageBar().pushMessage('Link: %s ' %link, ' %s' %path, level=Qgis.Success, duration=10)
         
    canvas = iface.mapCanvas() 
    
    # this QGIS tool emits a QgsPoint after each click on the map canvas
    pointTool = QgsMapToolEmitPoint(canvas)
    #left click runs display_point
    pointTool.canvasClicked.connect( display_point ) 
    
    canvas.setMapTool( pointTool )

Do I miss something that resets everything without reloading?