Just did some testing, if I connect the camera directly to my Ubuntu PC running kStars 3.4.0 it works just fine in MSC mode (as usual)
Trying the same controlling my RPi4/SM via kStars from my Win10 PC or directly via VNC:
[2020-02-23T20:27:43.187 Rom, normaltid DEBG ][ org.kde.kstars.indi] - Received new device Pentax DSLR K70
[2020-02-23T20:27:43.187 Rom, normaltid DEBG ][ org.kde.kstars.indi] - INDIListener: New device Pentax DSLR K70
[2020-02-23T20:27:43.203 Rom, normaltid INFO ][ org.kde.kstars.ekos] - Ekos received a new device: Pentax DSLR K70
[2020-02-23T20:27:43.203 Rom, normaltid INFO ][ org.kde.kstars.ekos] - "Remote devices established."
[2020-02-23T20:27:43.203 Rom, normaltid DEBG ][ org.kde.kstars.indi] - < Pentax DSLR K70 >: < CONNECTION >
[2020-02-23T20:27:43.218 Rom, normaltid DEBG ][ org.kde.kstars.indi] - < Pentax DSLR K70 >: < DRIVER_INFO >
[2020-02-23T20:27:43.218 Rom, normaltid DEBG ][ org.kde.kstars.indi] - < Pentax DSLR K70 >: < POLLING_PERIOD >
[2020-02-23T20:27:43.218 Rom, normaltid DEBG ][ org.kde.kstars.indi] - < Pentax DSLR K70 >: < DEBUG >
[2020-02-23T20:27:43.218 Rom, normaltid DEBG ][ org.kde.kstars.indi] - < Pentax DSLR K70 >: < SIMULATION >
[2020-02-23T20:27:43.218 Rom, normaltid DEBG ][ org.kde.kstars.indi] - < Pentax DSLR K70 >: < CONFIG_PROCESS >
[2020-02-23T20:27:43.234 Rom, normaltid DEBG ][ org.kde.kstars.indi] - < Pentax DSLR K70 >: < ACTIVE_DEVICES >
[2020-02-23T20:27:43.234 Rom, normaltid DEBG ][ org.kde.kstars.indi] - < Pentax DSLR K70 >: < DEVICE_PORT >
.
.
[2020-02-23T20:27:43.937 Rom, normaltid INFO ][ org.kde.kstars.indi] - Pentax DSLR K70 : "[ERROR] Camera_get_config failed (-7): I/O problem "
[2020-02-23T20:27:43.937 Rom, normaltid INFO ][ org.kde.kstars.indi] - Pentax DSLR K70 : "[ERROR] Can not open camera: Power OK? If camera is auto-mounted as external disk storage, please unmount it and disable auto-mount. "
[2020-02-23T20:27:43.937 Rom, normaltid DEBG ][ org.kde.kstars.ekos] - Pentax DSLR K70 is disconnected.
[2020-02-23T20:27:43.937 Rom, normaltid INFO ][ org.kde.kstars.ekos] - "Pentax DSLR K70 is disconnected."
[2020-02-23T20:27:43.937 Rom, normaltid INFO ][ org.kde.kstars.indi] - Pentax DSLR K70 : "[INFO] Debug is enabled. "
[2020-02-23T20:27:43.937 Rom, normaltid DEBG ][ org.kde.kstars.indi] - < Pentax DSLR K70 >: < DEBUG_LEVEL >
[2020-02-23T20:27:43.952 Rom, normaltid DEBG ][ org.kde.kstars.indi] - < Pentax DSLR K70 >: < LOGGING_LEVEL >
[2020-02-23T20:27:43.952 Rom, normaltid DEBG ][ org.kde.kstars.indi] - < Pentax DSLR K70 >: < LOG_OUTPUT >
I also tried to unmount the camera and then started kStars on the RPi, same message.