No output without delay before Serial.print

Hello everyone, I'm pretty new to the Arduino IDE, this Forum and microcontrollers in general. So please correct me if I posted in the wrong forum section or something similar. I couln't find an answer to my problem in this forum, on or anywhere else but please redirect me if an answer already exists somewhere.

I got a spare ESP8266 (D1 mini) from a friend and started trying out some basic code after reading a bit on the topic. I did install the CH340 Driver, the ESP8266 Microgear library and the ESP8266 Board Manager.

My Problem: I cant get the board to return the following code in the serial monitor without a delay between Serial.begin and Serial.print

void setup() {
  // put your setup code here, to run once:
  Serial.print("test1 ");


void loop() {
  // put your main code here, to run repeatedly:

If the delay is placed between the first and second Serial.print, only the second is shown in the serial monitor. For delay values smaller or around 135, I either get no Output at all or something like multiple question marks or "???t1 test2". I did see several beginner's instructions where similar code worked without the delay, hence my question.

The esp8266-Blink sketch on the other hand worked perfectly fine. I did also try differend baud rates (matching rates in the sketch and monitor and also different rates as I've read that that worked for some people online) and different Board Manager settings, neither worked with my board.

Sure, simply adding a delay wouldn't bother me for now, but I'd like to understand where this problem originates and how to fix it, as I'd probably like to use other people's code in the future.

Anything wrong about the code, my setup for esp8266 or is there something I missed entirely for Serial.print or the Arduino IDE to work?