Boot with no GUI issue

Hi to everyone,
I'm using antiX19.4 (Debian 10 based) with 4.9.0-264-antix.1-amd64-smp kernel.
My mobo is Biostar P4M800-M7A rev7.0, with:
Intel Pentium 4 521
Integrated GPU S3 UniChrome Pro

In recent days, when booting the machine it alternates between GUI and not GUI boot. So sometimes I boot the computer and as it ends boot log I get the login page but without GUI, only text based.
If I run runlevel I get "N 5". Here is the boot log when this happened:
Quote:

Sun Sep 12 22:02:35 2021: [....] Checking file systems...fsck from util-linux 2.33.1 Sun Sep 12 22:02:35 2021: boot: clean, 341/32768 files, 19187/131072 blocks Sun Sep 12 22:02:36 2021: homeantiX: clean, 16447/15532032 files, 1467594/62110464 blocks Sun Sep 12 22:02:36 2021: ??7[ ok 8??done. Sun Sep 12 22:02:36 2021: [info] Loading kernel module lp. Sun Sep 12 22:02:36 2021: [info] Loading kernel module ppdev. Sun Sep 12 22:02:36 2021: [info] Loading kernel module parport_pc. Sun Sep 12 22:02:36 2021: [info] Loading kernel module loop. Sun Sep 12 22:02:36 2021: [info] Loading kernel module it87. Sun Sep 12 22:02:36 2021: [....] Mounting local filesystems...??7[ ok 8??done. Sun Sep 12 22:02:37 2021: [....] Activating swapfile swap...??7[ ok 8??done. Sun Sep 12 22:02:37 2021: [....] Cleaning up temporary files...??7[ ok 8??. Sun Sep 12 22:02:37 2021: [....] Starting Setting kernel variables: sysctl??7[ ok 8??. Sun Sep 12 22:02:37 2021: [....] Setting up resolvconf...??7[ ok 8??done. Sun Sep 12 22:02:37 2021: [....] Skip starting firewall: ufw (not enabled)...??7[ ok 8??done. Sun Sep 12 22:02:38 2021: [....] Configuring network interfaces in background... ??7[ ok 8??done. Sun Sep 12 22:02:38 2021: [....] Starting RPC port mapper daemon: rpcbind??7[ ok 8??. Sun Sep 12 22:02:38 2021: [....] Starting NFS common utilities: statd idmapd??7[ ok 8??. Sun Sep 12 22:02:39 2021: [....] Cleaning up temporary files...??7[ ok 8??. Sun Sep 12 22:02:39 2021: [....] Setting up ALSA...??7[ ok 8??done. Sun Sep 12 22:02:39 2021: [....] Setting sensors limits...??7[ ok 8??done. Sun Sep 12 22:02:39 2021: [....] Setting up X socket directories... /tmp/.X11-unix /tmp/.ICE-unix??7[ ok 8??. Sun Sep 12 22:02:39 2021: INIT: Entering runlevel: 5 Sun Sep 12 22:02:39 2021: [info] Using makefile-style concurrent boot in runlevel 5. Sun Sep 12 22:02:39 2021: [....] Setting up console font and keymap...??7[ ok 8??done. Sun Sep 12 22:02:39 2021: [....] Starting enhanced syslogd: rsyslogd??7[ ok 8??. Sun Sep 12 22:02:40 2021: [....] Enabling power management...??7[ ok 8??done. Sun Sep 12 22:02:40 2021: [....] Starting ACPI services: acpid??7[ ok 8??. Sun Sep 12 22:02:40 2021: [....] Starting anac(h)ronistic cron: anacron??7[ ok 8??. Sun Sep 12 22:02:40 2021: [....] Starting periodic command scheduler: cron??7[ ok 8??. Sun Sep 12 22:02:40 2021: [....] Starting system message bus: dbus??7[ ok 8??. Sun Sep 12 22:02:41 2021: [....] Starting Avahi mDNS/DNS-SD Daemon: avahi-daemon??7[ ok 8??. Sun Sep 12 22:02:41 2021: [....] Starting bluetooth: bluetoothd??7[ ok 8??. Sun Sep 12 22:02:41 2021: [....] Starting Connection Manager:??7[ ok 8??. Sun Sep 12 22:02:42 2021: [....] Starting Common Unix Printing System: cupsd??7[ ok 8??. Sun Sep 12 22:02:42 2021: [....] Starting Bluetooth DUN daemon: dundee??7[ ok 8??. Sun Sep 12 22:02:43 2021: [....] Starting session management daemon: elogind??7[ ok 8??. Sun Sep 12 22:02:43 2021: [....] Starting mouse interface server: gpm??7[ ok 8??. Sun Sep 12 22:02:43 2021: [....] Starting NTP server: ntpd??7[ ok 8??. Sun Sep 12 22:02:44 2021: [....] Starting oFono Mobile Telephony Daemon: ofonod??7[ ok 8??. Sun Sep 12 22:02:44 2021: [....] Starting SANE network scanner server: saned??7[ ok 8??. Sun Sep 12 22:02:45 2021: [....] Starting slim: slim??7[ ok 8??. Sun Sep 12 22:02:45 2021: [....] Starting OpenBSD Secure Shell server: sshd??7[ ok 8??.

The runlevel seems fine, so does the "Starting slim ... [ok]" log. compared to when computer boots with GUI the boot log seems the same.
What I noticed is that it generally does the "no GUI boot" after I left my pc powered off for a longer time (a few hours).
As a new user I have no more ideas about how to solve, or understand, this issue. Thanks for your time.