@Rambali are you connecting to the modem via ethernet or wifi, or both. If you connect via both paths, are they both slow?
Can you log into the modem, navigate to the STATUS .... DOCSIS wan tab and copy the Downstream Overview, all the way to the very bottom of the Upstream Overview or OFDM/OFDMA section, depending on which modem you have. Select or highlight that entire table area, right click ..... Copy. Then open a new post and right click .... Paste. That whole table should past into a post so we can check the current signal levels.