Aeroad SLX Size recommendation

Hi all,
I started to take cycling more seriously in the past two years. However Iam exactly between two frame sizes regarding to the canyon size chart.

When I race – or ride longer distances like 75km plus my upper and lower back are hurting. Also from time to time my hands get a little numb.

Also when iam on the bike and turn the bar, the front tires are touching my toes if
I provoke it.

Currently I ride the Aeroad SLX in size M and I am afraid the frame is just too small and I should have taken an L.

On top regarding to every size chart it seems that my legs are relatively long – making it hard to me to find a reasonable frame size at any manufacturer.

I am wondering if there is anyone out there who has a similar body geometry and has found a good fitting road bike.

Thank you for your support!