I think that to realise a realistic bell sound electronically, you need to read up on audio DSP. and synthesis.
The reference to ADSR envelopes is completely relevant.
I remember (a long time ago) the only way we could ‘fake’ a bell sound live was using the ADSR and waveform generators in a professional synthesiser.
The reason bells ‘work so well’, is they ‘cut through’ ambient sound by having a significantly different waveform profile.
It’s a bit like synthesising the colour ‘gold’ compared with a ‘flat’ colour… Gold is a texture that reflects the immediate environment with respect to the viewer and prevailing light conditions…. Same with a bell in the soundscape.
TL;DR The easiest shortcut is an MP3 audio clip, otherwise you. need to generate a relatively complex audio waveform.