Raspberry Pi or Arduino - Is it possible to build a BMS without relays?

Hello, I recently had an argument with a colleague who tells me that you can't do a BMS on a Rapsberry or Arduino because there are no actuators, in other words relays.
Is he right?
Fibaro or Siemens systems are very expensive

You can connect external boards with relays or control inputs, temperature sensors to both platforms. Rapsi is more "high-positioned" if you know what I mean, for the BMS in my opinion the Arduino is more suitable.

Example actuators for Arduino

I see, but what about a BMS created on bluetooth technology?
I have heard that something like that can also be implemented, but how????

Added after 46 [minutes]:

And for the Arduino under the BMS is there any ready software???? How many boards like you have shown can be connected, per relay how many components can be connected????

for raspberry you have :
openhab(java) - dozens of communication protocols
domoticz(python) - simple but nice
jeedom - a very promising young project

for android there is for example Zodianet multi (paid)

these are just the ones I have tested and found subjectively worthwhile. There are plenty of these.

How many actuators can be connected to the Arduino?

lukas198820 wrote:

How many actuators can be connected to the Arduino?

The case is that in the simplest version of the Arduino (UNO), we have 14 digital inputs/outputs available (of which 6 can be used as PWM outputs). In this case, we could connect 14 simple actuators (e.g. LEDs, relay) to the Arduino.
For the use of a large number of such devices, extended versions of the Arduino have also been developed, such as the Arduino Mega, which has as many as 54 digital channels.
In addition, we can extend the capabilities of the platform at low cost using various components, such as sliding registers. More on this subject here .
Regards

Thanks to gglmaster.
And have you done such a BMS before?

lukas198820 unfortunately I didn't, but I did a couple of smaller projects (mostly for self-development purposes). However.
As for the BMS - I think it would be a good idea to look through the offer (presentations) of manufacturers of such systems and, based on them, create algorithms for the operation of our own system.
As for Arduino - it does not differ much in hardware from a regular atmega (and it has one, too), but a huge plus when it comes to constructing anything in this environment is a really large number of ready-made projects, tutorials and ebooks, from which you can learn and benefit a lot. Additionally, writing code in the Arduino "language" is much simpler than even pure C for AVR.
Regards